I found the following answer to a very similar question on another forum. The question on the other forum related to CL70 and the response is not mine...I'm simply suggesting this might answer your question as well. Wiring colours don't seem to match your bike but the concept might apply to your situation. Apologies if this is somehow in violation of any forum rules.
DY = Dynamo
SE = Selenium
The Dynamo features a permanent magnet rotor, so the faster it is turned, the more AC it generates. Technically a Dynamo is an alternator.
Your bike's Dynamo is unlike the automotive Alternator with its electric magnet rotor, where by varying Voltage to the magnet, AC output is altered.
Selenium rectifier was OEM on your bike, so the SE implies a connection to the rectifier.
Reason for this connection: with headlight ON, the DY winding White is connected via handlebar switch, to the Yellow which feeds the Rectifier. This boosts charge Amps to accomodate the headlight load. With headlight OFF, that DY winding is disconnected, preventing the battery from overcharging and boiling the electrolyte. The Yellow and Pink windings generate just enough charge to run everything but the headlight.